As for a conventional equipment management system, a facility equipment maker manufacturing facility equipment such as air conditioners and refrigerators, for example, develops centralized controllers for managing the facility equipment independently, and has the centralized controllers perform all the control necessary for the facility equipment (see Patent Document 1, for example).
Accordingly, the centralized controller must be equipped not only with a sequence control program corresponding to the standard functions of the facility equipment, but also with a sequence control program corresponding to a unique function of the facility equipment.
Since the sequence control program corresponding to the unique function of the facility equipment varies according to the unique function of the facility equipment, it is necessary to revise an existing sequence control program or to develop a new sequence control program in accordance with the unique function of the facility equipment.
However, since the sequence control program installed in the centralized controller is generally written with a special program language suitable for control, operation and the like, it is difficult for those other than engineers having a thorough knowledge of the program language to revise or develop it.
Thus, considering a development period or development costs of the program, it is difficult for the centralized controller to always cope with the unique functions of the facility equipment.
Besides the foregoing equipment management system, a system is developed which handles all the control necessary for the facility equipment with a programmable controller (see Patent Document 2, for example).
A sequence control program installed in the programmable controller has an advantage over the sequence control program installed in the centralized controller in that a user can create or revise it easily without knowledge of the program language.
However, since the program volume of the sequence control program expands to achieve fine control of the facility equipment with the programmable controller, it is necessary to prepare an expensive programmable controller, which makes it difficult to construct an inexpensive equipment management system.
Incidentally, since ordinary equipment suppliers who create sequence control programs and cope with individual apparatuses have usually little technical knowledge about specific facility equipment (such as air conditioners), it is difficult for them to realize the fine control of the facility equipment with the programmable controller.
Patent Document 1: Japanese Patent Laid-Open No. 9-257297/1997 (Paragraphs [0025] to [0026], and FIG. 2).
Patent Document 2: Japanese Patent Laid-Open No. 2001-197662 (Paragraph [0025], and FIG. 1).
With the foregoing configurations, the conventional equipment management systems have problems in that they have difficulty in coping with the unique functions of the facility equipment with the centralized controller, and that if they try to perform the fine control of the facility equipment with the programmable controller, they must prepare an expensive programmable controller because of the great program volume of the sequence control program.
The present invention is implemented to solve the foregoing problems. Therefore it is an object of the present invention to provide an equipment management system capable of coping with the unique functions of the facility equipment easily without using the expensive programmable controller.
Another object of the present invention is to provide a programmable controller and centralized controller applicable to the equipment management system capable of coping with the unique functions of the facility equipment easily.